Vulnerability · Published Jan 10, 2026 · Assigned by GitHub_M
CVE-2026-22703Cosign verification accepts any valid Rekor entry under certain conditions
Medium 5.5
In plain English
A medium-severity insufficient verification of data authenticity in cosign from sigstore. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact's digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact's digest, the user's public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user's identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | cosign | 2.6.3-r0 | ALPINE-CVE-2026-22703 |
| Debian:13 | cosign | no fix listed | DEBIAN-CVE-2026-22703 |
| Debian:14 | cosign | 2.6.2-1 | DEBIAN-CVE-2026-22703 |
| Go | github.com/sigstore/cosign | no fix listed | GO-2026-4309 |
| Go | github.com/sigstore/cosign/v2 | 2.6.2 | GHSA-whqx-f9j3-ch6m |
| Go | github.com/sigstore/cosign/v2 | 2.6.2 | GO-2026-4309 |
| Go | github.com/sigstore/cosign/v3 | 3.0.4 | GO-2026-4309 |
| Go | github.com/sigstore/cosign/v3 | 3.0.4 | GHSA-whqx-f9j3-ch6m |
| Ubuntu:25.10 | cosign | no fix listed | UBUNTU-CVE-2026-22703 |
| Ubuntu:26.10 | cosign | no fix listed | UBUNTU-CVE-2026-22703 |
Affected products (as reported)
Weakness: CWE-345 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
References
- https://github.com/sigstore/cosign/security/advisories/GHSA-whqx-f9j3-ch6m x_refsource_CONFIRM
- https://github.com/sigstore/cosign/pull/4623 x_refsource_MISC
- https://github.com/sigstore/cosign/commit/6832fba4928c1ad69400235bbc41212de5006176 x_refsource_MISC